The concept of lubricating large bearings using an air/oil mixture is known. One currently-available system is sold by Lubriquip, Inc., a unit of IDEX Corporation, of Cleveland, Ohio. Currently-available lubrication systems for equipment with large bearings employs standard divider valves which meter the correct amounts of oil for delivery to a plurality of bearing points. The oil is delivered to a mixing tee where it is combined with a stream of compressed air using an aspiration process. The air/oil mixture is then conveyed to the bearing points through pipes or tubes. The discharge of the air/oil mixture from the mixing tee is monitored by means of pressure switches which are necessary to detect if a lubrication line is broken or blocked. Specifically, if the line is broken, the pressure in the line will be too low; if the line is blocked, the pressure in the line will be too high.
The problems associated with the currently-available design includes the necessity of the separate mixing tees for each bearing point and the plumbing associated with the mixing tees, including the large number of air connections that are required. Still further, the current design requires a high pressure switch and a low pressure switch for each bearing point, or each air/oil mixture outlet. The currently-available system also provides a limited amount of air flow which is disadvantageous because it has been found that a larger air flow to the bearing points would be beneficial because higher air flow capability enables contaminants to be removed from the bearing housings during lubrication.
Further, by employing pressure switches for fault monitoring, two switches for each bearing point must be employed--a high pressure switch and a low pressure switch. Each switch must be individually adjusted for either high or low pressure conditions. Thus, two switches per bearing point must be adjusted and maintained. Still further, the currently-available pressure switches are not as accurate as desired.
Accordingly, there is a need for an improved air/oil lubrication system for heavy duty bearings which is less costly to manufacture, to maintain and to monitor.